WORKING Memory SHORT Term STM WM

07:23 PM, August 07, 2007

 Working Memory in Wiki ... a key article with a lot of meat! 

See espec the Baddeley and Hitch model: phonological loop and visual sketch pad

May 16, 2010 10:16 AM

Working memory is the executive and attentional aspect of short-term memory involved in the interim integration, processing, disposal, and retrieval of information. Working memory tasks include the active monitoring or manipulation of information or behaviors.

coined by Miller, Galanter and Pribram.  in the 60s.  Atkinson/ Shiffrin  68.

Most theorists today use the concept of working memory to replace or include the older concept of short-term memory

The central executive (see <a class="mw-redirect" href="/wiki/Executive_system" title="Executive system">executive system</a>) is, among other things, responsible for directing <a href="/wiki/Attention" title="Attention">attention</a> to relevant information, suppressing irrelevant information and inappropriate actions, and for coordinating cognitive processes when more than one task must be done at the same time.

Working Memory in the brain...

May 01, 2011 11:16 AM

<<I revisit this topic because of the LINK BTWN CONSC and WORKING MEMORY.

If consc is a diffuse, attractor network, then where and how is memory stored???>>

QV  Baddeley model of working memory:

multicomponent model of WM.  PL = phonolog loop:  info is refreshed by a rehearsal loop...

keep a 7 digit phone number going;

VSSP =  visuospatial sketch pad  for vision;  mental maps and visual images;

2 compoents:  visual subsystem (shape, color, texture) and a spatial subsystem for location.

The cenetral exec direct attn to relevant info.

Baddeley (2000)  added a 4th compoent:  the episodic buffer,  which holds reps that INTEGRATE phono, visual,and

spatial info  (and semantic info etc).  It is episodic because it BINDS info into a unitary episodic repres.

(but this is a temporary store as opposed to Tulving's  concept of episodic memory  << which is LT>>

COWAN  

regards working memory not as a separate system, but as a part of <a href="/wiki/Long-term_memory">long-term memory</a>. Representations in working memory are a subset of the representations in long-term memory. Working memory is organized into two embedded levels. The first level consists of long-term memory representations that are activated. There can be many of these, there is no limit to activation of representations in long-term memory. The second level is called the focus of attention. The focus is regarded as capacity limited and holds up to four of the activated representations.

Some researchers have argued<a href="#cite_note-18">[19]</a> that working memory capacity reflects the efficiency of executive functions, most notably the ability to maintain a few task-relevant representations in the face of distracting irrelevant information. The tasks seem to reflect individual differences in ability to focus and maintain attention, particularly when other events are serving to capture attention.

Others have argued (Halford) that the capacity of working memory is better characterized as the ability to mentally form relations between elements, or to grasp relations in given information....

Experimental Studies of WM:  Frequently REREAD this section... it is excellent and important.

what is the nature of the capacity limit?

One is that there is a limited pool of cognitive resources needed to keep representations active and thereby available for processing, and for carrying out processes.<a href="#cite_note-21">[22]</a> Another hypothesis is that memory traces in working memory decay within a few seconds, unless refreshed through rehearsal, and because the speed of rehearsal is limited, we can maintain only a limited amount of information.<a href="#cite_note-22">[23]</a>

Yet another idea is that representations held in working memory capacity interfere with each other.<a href="#cite_note-23">[24]</a>

There are several forms of <a title="Interference theory" href="/wiki/Interference_theory">interference</a> discussed by theorists:

retrieval competition  and  FEATURE STEALING or overwriing (in items that are similar)...

Time-based resource sharing model:  amt of forgetting depends on COGNITIVE LOAD... attn demands.

<<it seems obvious to me that BOTH  cognitive load and feature similarly/ interference are at work.

What is optimal for remembering is..  1) LOW cognitive load (lots of time for attention/ rehearsal/ refreshing

AND  2) NO or minimal interference...  do NOT try to learn two similar articles, eg... they will interfere.>>>

WM in the BRAIN

genetics:    ROBO1  for the phono loop. (severe dyslexia in one Finnish family due to familiar of axons to cross

midline  ;  this is NOT really a clue to normal functioning of WM,  since this is a sledge hammer)

physiology...  this is good;    DELAYED MATCHING TASK:  spatial WM in monkey:

3 card monte like experiment:   food under a cup...  monkey must decide which cup after a shutter comes down.

depends on PFC neurons...  also  delay-active neurons in posterior parietal cortex, thalamus, caudate and GP.

Goldman-Rakic...  DLPFC  connects with all these regions...  circuits within PFC can maintain WM thru networks

of excit pyramidal cells firing.

LOCALIZATION:  fMRI confirms  role of PFC in WM.

but WM is scattered all over the cortex;   spatial memory more in R hemisphere;  verbal and object more in L;

WM  recruits a network of PFC and parietal areas.  TMS interferes.

ROLE of PFC:  controlling attn,  slecting strategies, and manip info in WM  but

parietal cortex is involved with MAINTENANCE of WM  (possible also a role for parietal cor in exec fxn).

Acute and chronic STRESS impairs WM

NEURAL MAINTENANCE:  persistent firing of certain neurons in the delay period of WM to keep reps active.

How is binding accomplished?   synchrony, maybe.  oscillation in theta band  (4 to 8 hz)

theta does incr during WM load.

WORKING Memory SHORT Term STM WM

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